In some wireless networks, long term evolution (LTE) networks being one example, user equipment (UE) obtains uplink synchronization by transmitting a preamble to a base station (or evolved Node B, eNB) via a physical random access channel (PRACH). The preambles used in the PRACH are constant-amplitude Zadoff-Chu (ZC) sequences of a prime length, such that the cyclic auto-correlation of the ZC sequence is an ideal delta function and the cyclic cross-correlation of two ZC sequences with different root sequence indices is a constant of magnitude
      1                  N        ZC              ,where NZC is the ZC sequence length. At the base station, when a preamble is detected in the PRACH, its associated signal to interference plus noise ratio (SINR) can be estimated. The estimated preamble SINR can be used for the transmit power control (TPC) of the following first scheduled transmission on the uplink shared channel (ULSCH). As the preamble SINR estimate is primarily used for transmission on the ULSCH, the estimate should reflect the channel condition on the ULSCH even through the estimation is performed on the PRACH.